The improvement of the mechanical properties of steel by forging has long been known. Intensive compression by pressing or hammering reduces coarse crystalline structure into a fine-grained structure and thus reduces the porosity of the material, compacts it, and improves its ductility. Forging produces a particle compaction with a concomitant length increase in the area of two to three times.
The dissertation entitled "Theoretische und experimentalle Untersuchungen zum Formanderungsverlauf and zu Spannungszustand an einer Schmiedewalzanlage (GFM/Krupp) zur Herstellung von Stabmaterial" ("Theoretical and experimental tests of shape change and tension conditions in a forging system (GFM/Krupp) for producing bar stock") by Dipl. Ing. Tuke of Dortmund, produced for the Rheinisch-Westfalischen Technischen Hochschulle Achen in October 1979 describes a continuous forging system. Here the workpiece is pummeled by a plurality of annularly arranged hammers that substantially compact it. The billet thus treated is in fact struck perpendicularly and crosswise as well as diagonally at a 45.degree. angle to produce a workpiece with excellent grain structure. The system does not employ any rolling-mill technology and produces only a limited amount of finished workpieces.
In the periodical Stahl und Eisen (Vol. 110, No. 5, pp. 59-64) the high-precision rolling of bar stock in a fine steel wire installation of Moosstahl AG of Luzern, Switzerland is described. This publication discusses a high-pressure rolling system in a horizontal-roller frame and a vertical-roller frame. The method relates to the commercial production of bars with extremely accurately produced diameters and circular cross sections for fine steel and wire. There is no core compaction of the workpiece and none is intended.
The specialized literature Walzwerksanlagen (No. 2000.09.92 LD; September 1992; FIGS. 3 and 4) of SMS Schloemann-Siemag AG, of Dusseldorf, Germany shows the joining of a continuous-casting apparatus with a rolling installation for making fine steel out of billets. The goal here is a cost-efficient joining of the continuous-casting apparatus with the rolling installation so as to optimally use the latent heat in the strand.